A Rankine cycle comprises a vapor generating device for generating a super heated vapor by heating a liquid-phase fluid, an expansion device for generating a kinetic energy by expanding the super heated vapor in an isenthropic manner, a condenser for liquidizing the vapor expanded at the expansion device, a liquid pump for supplying a liquid-phase fluid to the vapor generating device, and so on, as disclosed in Japanese Patent No. 1540256 or Japanese Patent Publication No.2002-188402.
In a prior art vapor compression type refrigerating apparatus (an air-conditioning apparatus for a motor vehicle) utilizing the Rankine cycle, as disclosed in Japanese Patent Publication No. S63-96449, a compressor device is also utilized as an expansion device.
In the above prior art vapor compression type refrigerating apparatus (JP S63-96449), a refrigerating cycle and the Rankine cycle can not be operated at the same time, because the compressor device is utilized as the expansion device.
Furthermore, it may be difficult to practically carry out the invention of the above prior art (JP S63-96449), because it is not fully disclosed how the refrigerating cycle and the Rankine cycle are switched over from one to the other and how the Rankine cycle is performed.